TAU-7 repair?

[IPshooter]

A friend of mine, in the USA, has a TAU 7 that is 6 or 7 years old but only with a few hundred shots through it. It has developed a problem where it completely leaks out a new cylinder within a few seconds of installing it.

What are his choices for having it repaired and the approximate cost? He doesn't do much on the Internet, so that's why I'm inquiring for him.

TIA

Stan

[terrypchan]

My Tau-7 had the same problem and I easily repaired it by swapping out the O-ring that is nearest to the CO2 chamber in the top of the grip. The Tau-7 easily disassembles if you follow the instructions and the parts diagram in the manual. If it is the O-ring nearest the CO2 chamber in the top of the grip then you'll have to remove the CO2 chamber to get to it.

My older Tau-7 even had a spare set of O-rings when I bought it. The other O-ring to check is on the screw that adjusts the pellet speed (again see the diagram). Both of those O-rings get brittle over time and will need to be replaced eventually.

I'm sure Pilkguns has spare O-rings for the Tau-7 and if you're not up to repairing it yourself, then they will gladly do it for you at very reasonable a cost.

[BadMOJO]

We use the TAU pistols as our club guns for beginner shooters. I recommend that you stockpile o-rings because I replace at least one each week. Don't get me wrong, the TAU is a great gun for the money but it does have a tendancy to eat o-rings. Happy shooting!

[MSC]

Curious, would a dab of silicone or perhaps a seal-friendly oil like Crosman Pellgunoil be of any benefit before installing the seals? Perhaps extend the seal life? Just a thought....

Also, are you using Co2 powerlets (as opposed to bulk fill)? I remember hearing somewhere that seals wore quicker with this method.

[jer]

Oil or some small particle in the valve may also make the leakage. I was told by local importer that the nylon seal is not replaceable by end user. Some special tools are required.
Try to clean the valve. Take the grip off and remove and clean the piston (part number 27). Clean also the seal which is bottom of that hole where part number 27 is.

[Big X]

There´s an old Saying: It´s expencive to buy cheap.

I recon you have experienced that now.
Jump over the crap, but quality in the first place. And save yourself from tons of trouble.

[Guest]

There´s an old Saying: It´s expencive to buy cheap.

I recon you have experienced that now.
Jump over the crap, but quality in the first place. And save yourself from tons of trouble.

Depends. A club can buy three Tau AP's for its junior program for the price of one Steyr.

[Guest]

I've had more trouble with my Morini than with my two Tau 7's. On a dollar per problem basis, the Tau-7's are a better deal than any of the expensive air guns I've owned. None of them have been perfect and trouble free, but the Tau-7's are a VERY good pistol for the money, and they compare quite well with the more expensive pistols.

The only problem I've had with Tau-7's is that the seal around the CO2 cartridge piercing pin in one end cap had a pin hole leak. A good cleaning & a dab of epoxy fixed it just fine.

[bdutton]

I found this thread through a search and tried all of the things mentioned.

I am still getting a leak through the valve (#27). Now, in this diagram it shows #28 which is the valve packing...

http://www.74fdc.files.wordpress.com/20 ... ploded.jpg

When I took the valve out, I did not see this part... nor did I see it in the other 2 Tau 7 Juniors I have (which doesn't seem to harm the function of the other 2).

Where can I get this part? Is it necessary? How can I get this pistol repaired?

[Gwhite]

It's got to be in there, or they never would have worked. You need a good light & maybe some magnification to see it. The firing seal (#28) is made of a nylon like material, and they are a press fit into the pistol. They can be replaced, but you want to get a couple spares. The only way to get them out is with a large brass wood screw, which destroys the old seal.

Before you go that far, open it up & make SURE that everything is spotlessly clean. Then grease the conical part of the valve (#27) and try again (O-ring grease is the best). All it takes to get a leak is a tiny spec of dirt to get embedded in the plastic valve seat. Try firing it several times to try to reform the valve seat in case the debris created a burr. I've salvaged a couple with a good cleaning.

[Rover]

I had a couple or TAUs. I thought they looked good, but weren't.

Probably a IZH 46M, or better yet a Pardini K58 would be a better bet all around.

They may cost more, but you need not buy any extras.

[Gwhite]

We have about 20 Tau's and a similar number of IZH's. The Tau's are FAR more reliable, much easier to work on, and with the exception of the main firing seal, use standard O-rings. The ergonomics of the Tau's work out better for most of our shooters.

Especially now, it is also FAR harder to get parts for IZH's. Tau Brno has a web site, and if you can figure out how to get money to them, you can order pretty much anything you want. The IZH importer can't even get parts for them.

[yana]

Where is it leaking?
Some brand co2 bulbs give problems with the Tau 7, especially the Jr version.
Than they empty immediately after screwing on the cap and piercing. This is not a Tau problem but a bulb problem.
I never had this with crosman bulbs, I've had it several times with umarex bulbs. Their necks are different. But than it blows off backwards, totally whitening and freezing the piercer cap.

But before we start fixing, you áre cocking the pistol before inserting the bulb I hope? Otherwise it will indeed vent off through the barrel cause the valve is open.

If its venting through the barrel while it ís cocked, the problem is the valve seal.
They are quite hard to remove. You really have to screw something ínto the valve to remove it. It sits too deep to reach otherwise.
You can try tapping the valveseal though, and trying to seat it this way. I've solved a few slow leaks this way.
The old white Tau valve seals are VERY hard, they wont easily damage or dry out. But they can leak quite easily if interrupted.
The newer one's are blue iirc.
I sometimes add a tad of silicone grease to the barrel seals and piercercap seals. As recommended in the manual

[Gwhite]

The problem with the CO2 cartridges may be that the neck is a little long on some. If the piercing pin punctures the cartridge seal before the cap is screwed on enough to fully seat the O-ring, you will get a leak. I've never had that problem, but I've only ever used Crosman cartridges.

[yana]

I know.
But crosman bulbs are no longer available here. Umarex only

[Gwhite]

If you take some measurements with good cartridges & bad, you may be able to fix it by grinding the piercing pin just a little bit shorter. That way the O-ring can seal before the gas pressure is released. It may also have to do with the shape of the bottom end of the cartridges. The critical issue is the distance from the top of the threaded tube in the Tau to the top of the metal seal on the cartridge when it is in the tube. If that distance is significantly shorter with the Umarex cartridges, that could cause the problem you are experiencing. If it happens with only some cartridges, the difference good be quite small. Either that, or the quality control at Umarex is lousy.

Umarex probably gets them made by somebody else. If you can pin down the issue with some real data & dimensions, I'd contact Umarex. They may be interested to know if their vendor is selling them out of spec cartridges. They may also be happy to send you a box of cartridges for your troubles. I don't know about Umarex, but I've dealt with a lot of US companies that are delighted to get good customer feedback like that. The ones that just ignore problems when they are pointed out A) don't get my business, and B) don't get the business of all the folks I mention it to on the Internet.

[PFribley]

Listen to what Mr. White says. he knows those pistols inside and out.

[SPPcoach]

The only problem I've had with Tau-7's is that the seal around the CO2 cartridge piercing pin in one end cap had a pin hole leak. A good cleaning & a dab of epoxy fixed it just fine.

One of my athletes bought a used Tau-7 this month. Exact same problem.
I found that a metric 15mm x 19mm x 2mm o-ring to be a perfect fit for the CO2 cap.
Now onto the next problem . . .

[SPPcoach]

http://www.74fdc.files.wordpress.com/20 ... ploded.jpg

This is a big help! Any chance you have the link to the parts list to go along with this diagram?

[Gwhite]

The only problem I've had with Tau-7's is that the seal around the CO2 cartridge piercing pin in one end cap had a pin hole leak. A good cleaning & a dab of epoxy fixed it just fine.

One of my athletes bought a used Tau-7 this month. Exact same problem.
I found that a metric 15mm x 19mm x 2mm o-ring to be a perfect fit for the CO2 cap.
Now onto the next problem . . .

What exactly is "the next problem". I've spent about 10 years maintaining almost 20 Tau's for the college team I help coach.

Here's info on O-rings:

Tau-7 O-Rings.pdf

(223.29 KiB) Downloaded 380 times